K&N air filter?

[Guest remarcable]

I don't know about engine internals, but my intake tract is squeaky clean after 30k miles with the amsoil panel filter.

 

When I use a paper filter the car sounds much whinier and higher pitched and I get an annoying harmonic humming noise at highway speeds. With the amsoil I get a nice growl and no annoying noises.

[Guest 1 Lucky Texan]

Long story short - I'm pretty sure a carb backfire igniting an Amsoil filter is responsible for a fire in an auto I had just sold to a coworker . He blamed it on sabotage from bikers! We'll never know for sure. What a waste of a '69 datsun 2000 ragtop.

 

Carl

1 Lucky Texan

[Guest CROSSTBOLT]

Thanks, Josh, for those great articles! I will not be buying any K&N air filters. Anybody know where to get a Mahle paper element filter for our Subaru's?

 

Karl

[Guest spagemurray]

Carl On BITOG forum look at Used oil Analysis section and the air filter section. There is a lot of info and I have to visit several times a day to keep up. Worth it though and my Outback has benefited from what I learn't there.

[Guest 1 Lucky Texan]

Well, although I don't think the info there is as conclusive(as far as damning K&N) as you seem to believe, reading some of the threads has swung my opinion back to sticking with 'normal' paper type filters, either OEM or maybe one of those that tested well. Thanx for nudging us to check it out. I will be visiting it often - I find stuff like that interesting.

 

Carl

1 Lucky Texan

[Guest Subazoo]

They say K&N filters void there warranty for their products due to allowing the golfball-size particles to get by...

[Guest wrxsubaru]

A company can not void a warrenty for having a direct replacment aftermarket airfilter in the car instead of the OEM one, because the airfilter wares out and you can replace it with what ever one you want, unless the car company gives air fliters away for free,

 

It had this basicly written on the back of K&N box, under freqenty asked question, or something.

[Guest CROSSTBOLT]

Thanks, Spagemurray! Now, what is a BITOG and how do I get to it? Sorry for being so sorry on some of this stuff.

 

Karl

[Guest spagemurray]

http://WWW.BOBISTHEOILGUY.COM has about everything you'd need to know about oil, grease, oil and air filters including pressure drop tests, additives, gear oils, cleaners etc. My OB uses about 25% less fuel from what I learn't there. K & N is good for intended purpose (hi airflow with average filtering) but OEM or similar filters are best for minimal SI in your oil IMO.

[Guest Commuter]

BITOG = Bob is the oil guy... I've poked around the site a little bit, but that's all.

 

Just for fun, I'm going to throw a little fuel on the fire here on this topic. For the record, I have a K&N filter in my 97 OB. (In the process of cleaning it right now as a matter of fact.) People are concerned about dirt from the air, but should they be...

 

This <a href="http://www.synlube.com/motoroil.htm" target="top">page</a> is from the SynLube site - Mystery of Dirty Oil. I use the SynLube products in my Subaru. The page is rather lengthy.... the tone of the writing is rather condescending... but if you can get past that for a moment, there are some interesting 'numbers' buried in there.

 

Just a couple of highlights:

- An air filter will see about 10,000,000 gallons of air over it's useful life. (Consider that when you look at your "dirty" air filter.)

- Air speeds into the cylinder are in the hundreds of miles per hour... even up to super sonic. Exhaust speeds are even faster.

- Residence time in the cylinder is 1/20th to 1/200th of a second.

- Combustion temperatures are >2000F.

 

Imagine being that particle of dirt getting into the engine. Not only do you have to settle out of the tornado like storm in a micro fraction of a second... and survive the combustion temperatures... you also have to get past the piston rings to get into the oil.

 

Now.. I have no idea about the supposed relationship between K&N filters and elevated Si levels. No comment. I'm not taking any sort of stand or opinion on this. I'm just pointing out the conditions that the particle of dirt that gets by the filter faces inside the engine. I don't think many consider that aspect.

 

Commuter

[Guest 1 Lucky Texan]

EXCELLENT point commuter!

Also, buried in one of the posts I read at the BITOG site was the fact that the spectrographic tests can not distinguish between SI in quartz vs SI in - say - some silicone lubricant or silicon/aluminum alloys! Also, I suspect quite a bit of the wear an engine experiences goes out the tailpipe as oxidized (burnt) iron,etc.. However, there are some intersting posts about oil analysis of UO from aircraft having spotted severe (potentially lethal) mechnanical problems.

I think some of the following would be interesting tests.

1. What is actually stuck in the air filters?

2. " " " " " " oil filters?

3. What is going out the tailpipe?

4. What is the size of any particles in crankcase which are harder (capable of abrading) than engine moving parts?

5. What is actually lying in the bottom of the oil pan? how does it change with time?

 

BTW- I'd be interested in knowing how to maintain care and increase perf./eff. of my new OBW without sacrificing longevity.

 

Carl

1 Lucky Texan

[Guest Commuter]

I can give you some info on your point 4. Again... this comes primarily from the SynLube site (somewhere under oil filters I think), but I've seen confirmation from some Amsoil info as well.

 

Regarding particle size. Here is a summary of some information that I found.

 

Particles over 65 microns will be trapped by the filter or settle out in the pan.

 

Most cellulose filter elements will not get particles much smaller than 20 micron.

 

A premium cellulose filter element will get down to about 15 micron.

 

A MircoGlass filter element will get down to the 5 to 10 micron range.

 

Smaller particles, eg a few microns or less, just "go along for the ride" in the oil.

 

The wear particles that are most damaging and that cause the most wear in automotive engines are in 12 to 24 micron range

 

So... a good filter pays off. Many cheap filters let the bulk of the most damaging particle sizes right through!

 

Commuter

[Guest 1 Lucky Texan]

So there's like these one thousandth of an inch, 1200 grit, most folks could feel 'em with their fingers, particles running around in my engine with the oil?

 

Now, how hard are they? are htye like mushy lumps of graphite or are they quartz? How much of either?

 

Carl

1 Lucky Texan

(hey-what brand of microglass filter should I look for?)

[Guest remarcable]

So where do we get microglass filters for our subies?

 

The only options I've found are the K&N/Amsoil foam/mesh filters and the subaru OE paper filters.

[Guest Commuter]

He asked about the crankcase. The info I gave pertained to the <strong>oil</strong> and oil filters, <strong>not</strong> air filters.

 

I'm using the SynLube oil filter. It is simply an unmarked ACDelco Ultraguard Gold filter, p/n UPF1127. It is a bit smaller than the OEM filter, but has the proper thread and a gasket diameter that's suitable.

 

Last I heard, these filters were no longer being made. (Dana is/was the manufacturer.) They are very expensive and people weren't buying them. I don't know what else is available for microglass filters.

 

The Purolator PureONE is a very good filter. It has some synthetic media (polymer, not glass to my understanding) that filters to smaller particle sizes. If you buy a case of 12 at once, you can get them for a decent price (eg 50% off).

 

Commuter

[Guest 99OBSter]

Ok, after reading all this, I've decided to go back to stock. I had a K&N cone filter, no air box, and I just swapped it back to the oem filter. Man, I miss the high end, though. I might try an Apex'i cone filter, as I think it is paper or something like that.

 

We'll see.

[Guest spagemurray]

I use PureONE on my 'other car' a Mazda 626 turbo. Sticking to OEM on the Outback for now.

[Guest subyluvr2212]

Although I don't have any equipment to test the amount of 12-micron particles flowing through my air filter, nor do I want to tear my perfectly-running engine apart to find out what miniscule damage they're causing, but I just put a Purolator air filter, A24278, and the trusty Purolator L14460 oil filter. I am just peachy with the power and performance of the air filter, and the oil filter seems to do fine, it at least comes off easily, unlike a Bosch...

[Guest Setright]

There are so many stories out there, about all sorts of different products. What you need to do is put on your "bull****-filter" and use some commen sense and basic logic.

 

The best independet test I've seen, one that built on sound principles and repeatable experiments, concluded that in terms of flow, there is no advantage of paper over oiled cotton. When both are NEW!

 

The good thing about oiled cotton is that it continues to flow remarkably well over a long period of time. Paper elements tend to clog quickly.

 

With respect to particle sizes that slip through either: There might be a small difference, but the particle sizes that are relevant are too small to do engine damage. What they do produce is added resistance. They do however flow out of the engine when you drain the oil. Thats why they show up in the UOA.

 

I like to replace my engine oil every 10,000 km, and cannot sense any difference in engine performance. (This distance equates to three months driving.)

I once left it 12,000 km, and noticed a small improvement in performance immediately after changing oil. It would seem that SI levels had hit a level where it could begin to hinder the oil's perfomance.

 

By the way, I use Mobil 1. 5-50W in summer, 0-40W in winter, and my EJ22 consumes a litre of oil over those 10,000km.

I have been running it for over two years and nearly 100,000km and no change in oil consumption. Total mileage is 283,000km.

[Guest Legacy777]

well put!!

[Guest spagemurray]

Mobil 1 5W50. I'm thinking you must live in Oz?

[Guest andywatson]

I had no idea my post would get so many replies. Usually I'm lucky if I get one or two people to respond.

 

I wish I'd asked about K&N air filters before I went out and bought one. Now I'm starting to wonder if I should go back to paper filters.

 

Would anyone like to buy a slightly used K&N air filter (~500 miles).

[Guest Legacy777]

The K&N filter will be fine. k&n wouldn't sell so many if they were causing engine damage.

 

There is a lot of data out there in terms of oil analysis, particles, blah blah. Different people are going to interpret it differently.

 

If it gives you better peace of mind to run paper, run a paper, but I wouldn't loose any sleep over running the k&n.

[Guest subyluvr2212]

I ran a K&N filter for a few thousand miles before I tried a cone filter, then back to the box with a paper filter. I really didn't find the K&N to give THAT much performance, a little throttle response at best... Of course, I think everyone here is smart enough not to buy into the "20-hp" gains from a freeking air filter

 

Honestly, I think K&N's only advantage is that you can simply clean and re-oil the filter as many times as you need to. K&N claims this only needs to be done about every 40,000 miles in normal driving conditions, meaning you probably won't keep the car long enough to do it six times...

 

However, how much is the re-oil kit? Isn't it like 8 bucks? The price of a brand-new paper filter??? Hmmmm...

[Guest andywatson]

I made the mistake of changing the original fuel filter (w/ 70k miles through it) and the air filter at the same time. My car is definitely more responsive and has more power, but I don't know which one of the two filters (fuel or air) made the difference. I might throw the old air filter back in, just to see what happens.